Transmission module for pneumatic tool

Abstract

A transmission module includes a sleeve member, a cover disc, a hammering portion and an axle. The sleeve member has a rear disc and a cylinder body. A receiving space is defined between the rear disc and the cylinder body. The rear disc is formed with a teethed bore. The inner surface of the cylinder body is formed with at least one axially-stretched rib. The cover disc is disposed on the open end of the receiving space. The cover disc is formed with an axial bore. The hammering portion includes at least one rotary hammer, which is received in the receiving space. The rotary hammer has a through hole and a positioning groove. The rib is engaged with the positioning groove. The axle has a driven end and a working end. The driven end is inserted through the axial bore and mated with the through hole.

1 . A transmission module for a pneumatic tool, comprising:
 a sleeve member, having a rear disc and a cylinder body axially extended from the rear disc, a receiving space being defined between the rear disc and the cylinder body, the receiving space having an open end, the rear disc being formed with a teethed bore, the cylinder body having an inner surface and an outer surface, the inner surface is formed with at least one axially-stretched rib;   a cover disc, disposed on the open end of the receiving space, the cover disc is formed with an axial bore communicated with the receiving space;   a hammering portion, comprising at least one rotary hammer, the rotary hammer being received in the receiving space, the rotary hammer having a through hole and a positioning groove, the rib being engaged with the positioning groove so that the hammering portion and the sleeve member being in a rotational operative relationship; and   an axle, having a driven end and a working end, the driven end being inserted through the axial bore and mated with the through hole of the rotary hammer, the working end being protrusive from the cover disc.   
     
     
         2 . The transmission module of  claim 1 , wherein the inner surface of the cylinder body is formed with two opposite plane stages and two opposite axially-stretched ribs, the ribs are radially inward protrusive from the plane stages respectively, the hammering portion comprises two rotary hammers, each of which has a positioning groove to engage with one of the ribs, each rotary hammer has a non-circular through hole, the driven end is formed with two engaging shanks to mate with the non-circular through holes of the rotary hammers respectively. 
     
     
         3 . The transmission module of  claim 2 , a distance is defined between the plane stages and the open end of the receiving space, the cover disc is formed with a stepped portion extended toward the rear disc, a thickness of the stepped portion equals to the distance. 
     
     
         4 . The transmission module of  claim 1 , wherein the cylinder body is formed with at least one bore communicated with the receiving space. 
     
     
         5 . The transmission module of  claim 4 , wherein the at least one bore is slanted formed on the cylinder body. 
     
     
         6 . The transmission module of  claim 4 , wherein the bore is stepped and has a wide portion and a narrow portion, the wide portion is adjacent to the outer surface of the cylinder body, the narrow portion is adjacent to the inner surface of the cylinder body. 
     
     
         7 . The transmission module of  claim 1 , wherein the cover disc is formed with an annular wall axially extended outward, the annular wall surrounds the axial bore. 
     
     
         8 . The transmission module of  claim 1 , wherein a diameter of the cover disc equals to an inner diameter of the cylinder body, the cover disc is formed with two opposite arms radially extended outward, the cylinder body is formed with two opposite slots to engage with the arms respectively.